The present invention relates to an image processing method and apparatus and, more particularly, to an image processing method and apparatus which draw figures in accordance with instructions from data source.
In a conventional printing device which outputs figures, the following process is performed by using a cache memory. First, bitmap information of character patterns which has been generated is stored along with character sizes, character codes, and the like, and, when a character pattern of an arbitrary size is to be generated from outline character data, the stored bitmap information is searched whether or not there is bitmap information of the character pattern to be generated. If there is, the searched bitmap information is used. This process is used to prevent the disadvantage, as much as possible, in which drawing characters based on outline character data requires a much longer time than the drawing of characters based on bitmap patterns whose sizes are fixed in advance.
In the aforesaid conventional method, process using a cache memory, as described above, is not performed other than to form characters. The reason for this is that figures use the same patterns less often than characters, and have variety of pattern sizes. Therefore, process for forming figures by using a cache memory would be very complicated comparing to process for generating characters, thus an apparent advantage, such as to shorten processing time remarkably, can not be expected. Contrary to character generation, large capacity of memory would be necessary for storing figure patterns, and it would take considerable time to search all the stored figure patterns in the memory. Thus, above disadvantages of processing figures by using a cache memory exist.
Regarding generating characters, the aforesaid process using a cache memory is employed only to characters of small size. This is because frequency of using characters of large size is less often than that of small size, and in addition, the capacity required for storing character pattern increases in proportion to square of character size. Accordingly, disadvantages to generate large characters by using a cache memory exist as in the case of forming figures.